Enterprise and other collaboration applications and servers, such as the IBM® Lotus Domino server, facilitate communication (e.g., email, messaging) and other collaboration via network communications. EMC® Avamar® is a de-duplication backup software and system. Avamar® maintains a cache file on the client system being backed up which contains SHA-1 hashes of the data which has already been backed up to the Avamar server. This file will be referred during each backup operation to identify the data that has been backed up onto the Avamar server, e.g., to avoid duplicative back up of the same data in a current or subsequent backup.
In the case of the IBM® Lotus Domino server, a backup agent interacts with the server to obtain user data and feeds the data to a de-duplicating backup process. The backup process computes the SHA-1 hash of the data during backup and looks it up in the local cache. If it finds the computed hash in the cache, then the data will not be transferred to the Avamar server; instead just the hash of the data is sent to the server, which is much smaller in size as compared to original data. If the computed hash is not present in the local cache, then the data is transferred to the Avamar server and its hash is added to the cache.